code: def test_exp_save_unchanged(tmp_dir, dvc, scm):
      setup_stage(tmp_dir, dvc, scm)
      dvc.experiments.save()
  
file_path: dvc/tests/func/experiments/test_save.py
imports: import pytest
  from funcy import first
  from dvc.repo.experiments.exceptions import ExperimentExistsError, InvalidArgumentError
  from dvc.repo.experiments.utils import exp_refs_by_rev
  from dvc.scm import resolve_rev
label_desc: Use image node_id 2 for calling a global function with example usage: test_exp_save_unchanged(tmp_dir, dvc, scm) without return types